Bone marrow sampling, a term which includes both biopsy and aspiration, is used in the diagnosis and evaluation of many diseases. These include malignant conditions, especially leukemias, lymphomas and myelomas, disorders of blood and lymphoid cell production, and many other illnesses. Repeated examination of bone marrow may be required to monitor athe course of these conditions or the effects of treatments that may affect the bone marrow. The objective of the work proposed here is to develop a marrow sampling device which will penetrate the bone cortex in a rapid and controlled manner, having design features that will minimize tissue damage, combine biopsy and aspiration functions in a single device, and reduce patient discomfort. To accomplish this objective, a number of novel prototypic devices will be designed, fabricated and tested. The work proposed represents the rational application of engineering principals to a clinical device, followed by systematic and objective testing to arrive at the best combination of features. The resulting technological innovation will have a great clinical and commercial potential.